This project is a family genetic stud), comparing childhood onset schizophrenia and attention deficit hyperactivity disorder. The objective of this study is to identify genes associated with different facets of the schizophrenia phenotype. Specific Aims 1. To determine the rate of schizophrenia and Schizophrenic Spectrum Personality Disorder (SSPD) by direct interviews of first degree relatives, and by family history for second degree relatives, of children with onset of schizophrenia prior to thirteen years of age. To compare the rates of schizophrenia and SSPD among the first and second degree relatives of schizophrenic children to those observed in children with ADHD and normal control children. 2. To test the hypothesis that certain attention and information processing (AIP) Impairments index a genetic liability to schizophrenic disorder by determining if there is an increased aggregation of certain impairments among the first degree relatives of schizophrenic children as compared to the first degree relatives of children with ADHD and normal control children. 3. To replicate findings that schizophrenic probands have reduced total cerebral volume and reductions in the volume of the midsagittal thalamic area which exceeds the reduction in total cerebral volume, and enlargements of the caudate and putamen. 4. To identify genes associated with the presence of schizophrenia, SSPD, AIP. impairments and changes in volumes of brain structures in schizophrenic probands and their siblings.